THE LAST OF TEE GASES. 



467 



Just as the tube containing carbonic acid was 

 placed in the tube containing sulphurous acid, so 

 is a tube containing oxygen inserted in the long 

 tube containing the now solidified carbonic acid. 

 This tube is five metres long, fourteen millime- 

 tres in exterior diameter, and only four in in- 

 terior diameter — the glass is very thick. The 

 whole surface of this tube, except the ends which 

 project beyond the ends of the carbonic-acid tube, 

 is surrounded by the frozen carbonic acid. 



One end of this tube is connected with a 

 strong shell containing chlorate of potash, the 

 other end is furnished with a stopcock. 



When the tube was as cold as its surroundings, 

 heat was applied to the chlorate, and a pressure of 

 500 atmospheres was registered ; this descended 

 to 320. The stopcock was then opened, and a 

 liquid shot out with such violence that none could 

 be secured, though we shall hear of this soon. 



Pieces of lighted wood held in this stream 

 spontaneously inflamed with tremendous violence. 

 In this way, then, has oxygen been liquefied at last. 

 But this result has no sooner filled us with sur- 

 prise than it has been completely eclipsed. On 

 the last day of December, a week after the meet- 

 ing of the Academy to which we have referred, 

 M. Cailletet performed a series of experiments 

 in the laboratory of the Ecole Normale at Paris, in 

 the presence of Berthelot, Boussingault, St.-Claire- 

 Deville, Mascart, and other leading French chem- 

 ists and physicists, using the same method as 

 that formerly employed for oxygen, and he then 

 and there liquefied hydrogen, nitrogen, and air ! 



M. Cailletet first introduced pure nitrogen gas 

 into the apparatus. Under a pressure of 200 at- 

 mospheres the tube was opened, and a number 

 of drops of liquid nitrogen were formed. Hydro- 

 gen was next experimented with, and this, the 

 lightest and most difficult of all gases, was re- 

 duced to the form of a mist at 280 atmospheres. 

 The degree of cold attained by the sudden release 

 of these compressed gases is scarcely conceivable. 

 The physicists present at the experiment estimated 

 it at —300° C. 



Although oxygen and nitrogen had both been 

 liquefied, it was deemed of interest to carry out 

 the process with air, and the apparatus was filled 

 with the latter, carefully dried and freed from 

 carbonic acid. The experiment yielded the same 

 result. On opening the tube a stream of liquid 

 air issued from it resembling the fine jets forced 

 from our modern perfume-bottles. 



These more recent results are all the more 

 surprising as, at an earlier stage, hydrogen, at a 

 pressure of 300 atmospheres, has shown no signs 

 of giving way. 



These brilliant and important results, though, 

 as we have said, they give us no new idea on the 

 constitution of matter, open out a magnificent 

 vista for future experiment. First, we shall 

 doubtless be able to study solid oxygen, hydro- 

 gen, and air, and if MM. Pictet and Cailletet suc- 

 ceed in this there will then be the history to 

 write of the changes of molecular state, probably 

 accompanied by changes of color, through which 

 these elemental substances pass in their new 

 transformations. 



There is a distinct lesson to be learned from 

 the sources whence these startling tours deforce 

 have originated. The means at the command of 

 both MM. Cailletet and Pictet arise from the in- 

 dustrial requirements of these gentlemen, one for 

 making iron, the other for making ice. 



Why, then, in England, the land of practical 

 science, have we not more men like MM. Cailletet 

 and Pictet to utilize for purposes of research the 

 vast means at their disposal, or at all events to 

 allow others to use them ? 



It is also clear thjit-to cope with modern re- 

 quirements our laboratories must no longer con- 

 tain merely an antiquated air-pump, a Leyden 

 jar, and a few bottles, as many of them do. The 

 professor should be in charge of a work instead 

 of an old curiosity shop, and the scale of his op- 

 erations must be large if he is to march with the 

 times — times which, with the liquefaction of the 

 most refractory gases, mark an epoch in the his- 

 torv of science. — Nature. 



